The present invention generally relates to windowed members and, more particularly, to modifications to window sashes of windows formed of extruded polymeric materials, for improving the shock resistance of the windowed member.
Windowed members of all shapes and types, i.e., windows, swinging doors, sliding patio doors and the like, have evolved in the last years with the advent of new materials and manufacturing techniques. The sashes and frames that support the window panes have been modified extensively and departed from the traditional wood or metal materials to be replaced by extruded polymers, such as polyvinyl chloride (PVC). For instance, a window pane may be secured in a sash fabricated of elongated profiled polymeric extruded members forming rectangular frames. The process of extrusion enables the efficient production of high-density rigid members, with air pockets that ensure a high insulation value for these members. Furthermore, the assembly of elongated extruded members is easily performed by beveling end surfaces of the elongated members to then weld outer peripheries of the beveled surfaces of adjacent and perpendicular elongated members, to form a rectangular frame for supporting the window pane. In some instances, metal reinforcement is added to the rectangular frames formed of extruded members, such as steel or aluminum members.
The weld between the abutting joints of the polymeric members has been known to be a weak area of the structural component formed by the joined polymeric members. U.S. Pat. No. 4,601,768, issued to Bouyoucos et al. on Jul. 22, 1996, and U.S. Pat. No. 5,748,409, issued to Girard et al., on May 5, 1998, provide methods and apparatuses for overcoming the deficiencies related to the use of welding for interconnecting polymeric extruded members.
In the window industry, the windows are subject to high standards of quality and must go through series of tests in order to ensure their structural integrity. For instance, in the southeast regions of the United States and in the Caribbean countries, the standards have high thresholds, as these regions are subjected to severe weather conditions, including a hurricane season. In regions of Texas and in some parts of Florida, U.S.A., new standards have been established for testing the resistance to wind-borne debris impact. The tests involve the impacting of various missiles on various points of the window pane of a window. A typical standard for wind-borne debris impact testing of windowed doors consists of a large-missile impact test for windows, doors, skylights, glazing and shutters, in which a missile such as a 2xc3x974 timber weighing 9 lb is impacted at two different locations on a window pane at 50 ft/sec, and the window pane must survive these impacts without penetration. The two different locations may be, for instance, at the center of the window pane and within six inches of a corner. The missile impact portions of the test are followed by cyclic pressure testing, which will have the windows subjected to cycles of outward- and inward-acting pressure. In order for a specimen to pass the impact tests, it must not have, for example, tears or cracks longer than five inches or openings through which a three-inch sphere can pass.
Some window frames or sashes formed of plastified elongated extruded members interconnected by weld seams have been known to fail by the cracking of the weld seam during such impact tests and/or following cyclic pressure testing. On the other hand, if the weld seams are rigid enough to sustain such impact testing without cracking, the window pane often does not resist the missiles, as the rigid weld seams do not absorb enough of the shock waves. The rectangular frames may even resist to the shock propagation of the window pane due to the high rigidity of the weld seams, and the window pane often shatters because of this.
It is a feature of the present invention to provide windowed members formed of extruded polymeric materials having an improved resistance to impact shock.
It is a further feature of the present invention to provide the windowed members having an improved resistance to impact shock without having metal reinforcement.
According to the above feature of the present invention, from a broad aspect, the present invention provides a windowed sash of the type having at least one window pane supported in a window sash. The window sash consists of elongated profiled polymeric members interconnected by weld seams at joints therebetween. The window sash is adapted to be mounted in a frame. At least one hole is in contact with at least one of the weld seams interconnecting the elongated profiled polymeric extruded members for distributing, at least partially, stress sustained by at least one of the window pane and the window sash when subjected to shocks so as to prevent at least one of the weld seams, the elongated profiled polymeric extruded members and the window pane from cracking.
According to a further broad aspect of the present invention, there is provided a method for increasing a shock resistance of a windowed sash. The windowed sash has a window sash being formed by elongated profiled polymeric extruded members interconnected at joints by weld seams, and a window pane supported in the window sash. The method comprises the step of providing at least one hole in contact with at least one of the weld seams for distributing, at least partially, stress sustained by at least one of the window pane and the window sash when subjected to shocks so as to prevent at least one of the weld seams, the elongated profiled polymeric extruded members and the window pane from cracking.